Designed in the mid-1970s as a replacement for the M1 helmet and previous fragmentation vests, prototypes of the PASGT were tested in the late 1970s before being fielded in the early 1980s.

The shell is made from 19 layers of Kevlar, a ballistic aramid fabric treated with a phenolic resin system, and is rated at Threat Level IIIA.

This practice continued with the adoption of the LWH, but fell out of use and was discontinued because the mounting base for night vision devices covered the emblem, and required a hole in the fabric to attach, defacing the symbol.

It first saw use in combat in 1983 during Operation Urgent Fury in Grenada, became standard issue for the U.S. military in 1985, and completely replaced the M1 helmet for frontline troops by the end of the decade.

The PASGT system is still used by some U.S. allies and still sees some continued limited use in the U.S. military as of 2017, serving as one of the options available for sailors assigned to duty aboard U.S. Navy and Coast Guard vessels.

While generally incapable of stopping rifle bullets, the PASGT vest provided better protection against shrapnel and reduced the severity of injuries from small arms fire when compared to the M-69.

Based on testing conducted for the Brass Fetcher Ballistic Testing Company, former ARDEC research engineer John Ervin stated that the PASGT vest is equivalent to NIJ level II or IIA protection: able to stop multiple 124-grain 9×19mm FMJ pistol rounds to its main torso panels (front and back), but susceptible to several closely spaced rounds or shots to the thin neck and shoulder panels.

[21] The ISAPO weighed about 16.5 lb (7.5 kg) and consisted of a carrier to hold two protective ceramic plate inserts.

A PASGT armor system with overvest weighed more than 25.1 lb (11.4 kg)[22] and was criticized by many U.S. troops as unacceptably cumbersome in combat.

The inner and outer cover, shoulder pads and front closure flap of the vest are water repellent treated 8 oz.

While it had been phased out as frontline body armor by the start of the Iraq War in 2003, the PASGT vest saw some limited wear and usage by U.S. military personnel during the early stages of the war, where it was worn behind the frontlines by rear-echelon support personnel and navy sailors such as Seabees.

Some U.S. Army soldiers used old PASGT vests as makeshift armor for their vehicles in the absence of actual up-armor kits.